This paper reviews recent developments in methods for dealing with weak instruments (IVs) in IV regression models. The focus is more on tests and confidence intervals derived from tests than on estimators. The paper also presents new testing results under "many weak IV asymptotics," which are...

This paper considers tests of the parameter on endogenous variables in an instrumental variables regression model. The focus is on determining tests that have certain optimal power properties. We start by considering a model with normally distributed errors and known error covariance matrix. We...

This paper considers the use of the polynomial distributed lag (PDL) technique when the lag length is estimated rather than fixed. We focus on the case where the degree of the polynomial is fixed, the polynomial is constrained to be zero at a certain lag length q, and q is estimated along with...

This paper studies the real estate brokerage industry in Greater Boston, an industry with low entry barriers and substantial turnover. Using a comprehensive dataset of agents and transactions from 1998-2007, we find that entry does not increase sales probabilities or reduce the time it takes for...

The U.S. airline industry went through tremendous turmoil in the early 2000's. There were four major bankruptcies and two major mergers, with all legacy carriers reporting a large profit reduction. This paper presents a structural model of the airline industry, and estimates the impact of demand...

Under the TRIPS agreement, WTO members are required to enforce product patents for pharmaceuticals. The debate about the merits of this requirement has been extremely contentious. Many low income economies claim that patent protection for pharmaceuticals will result in substantially higher...